Resistance switch



June 6, 1950 w. E. BAKER RESISTANCE swrrcu 2 Sheets-Sheet 1 Original Filed Feb. 4, 1949 Inventor W/uM/v 5 BAKE? Attorney June 6, 1950 Original Filed Feb. 4, 1949 W. E. BAKER RESISTANCE SWITCH 2 Sheets-Sheet 2 INVENTOR. W/Ll/AH E. BAKE i Patented June 6, 1950 UNITED STATES PATENT OFFICE.

RESISTANCE SWITCH William 'E. Baker, Chickasha, kla., assignor of twenty-six and twoethirds per cent to Wiley True 'twenty-sixand two-thirds per cent to Boy I. Edwards, ten per-cent to Randall H. Sharpe, and-temper cent to- W. B. Jones and Edward BI J ordan- Original application February 4,'1949, Serial No. 74,582.: Dividedand'this application August 31, 1949, Serial No. 113,390

6 Claims. (Cl. 201-48).

This invention relates to. a.resistanceswitch and the present application constitutes a division.

from b'ycopending applicationfiled February 4, 1949, Ser. No. 74,582.

One object of the invention. is to. rovide a. switch adapted for carrying high voltage and including in its construction. a resistance which is graduallybrought into and gradually engaged by amovable contact as theswitch isclosed. 1

Another object'of theinvention is-to provideaswitch wherein -a block carrying .the.resistance and a stationary contact is tiltably. mounted in a housing or casing and also carries-a movablecontact which is gradually movedinto and out of.en-.

gagement with the resistance duringtilting movement of the block;

Another object of the .inventionls to provide a.

switch of this character wherein the block is yields ably held in -a tilted position effecting complete engagement of the movable contact with. the resistance,.the-block being tilted to a position moving the contact out of. engagement with the resistance by asolenoid which is mounted in the casing or switch box and rests uponthe bottom of the box.

Another object of the invention is to provide the switch with a casing or box havinga closure at its front which is movable to opened and closed positions and formed with an opening through which a pin. carried. by the core of the solenoid projects so that the core may be manually moved to effect opening of the switch, there being a latch provided for'engaging the pin and releasably holding the switch opened.

Another object of the invention is to providea switch having a spring for tilting the block to a closed positionso mounted that adjustments may be made to regulate tension of the spring.

Withthese and other objects in view the invention consists of a special construction and arrangement of parts illustrated in the accompanying. drawings wherein:

Fig. 1 is a, view showing the switch box in vertical section and mechanism within the box'in' front elevation with aportion-of the'movable contact broken away.

Fig. 5 is =a'sectionalview taken vertically through Figure 4.-

Fig. 6 is a .front elevation showing the-resist ance coil and the carrier forthe same.

Fig.7 is a rear'view of the carrier and conductorstrips 'for connecting: the "coils in series.

This improved switch has a box or housing I-' which may be-formed of-metal or other suitable: material. The boxis mounted vertically :upon a wall, instrument board, Orother suitable support when in use and is open at its front; theopen' front of- .the housing-or box being normally closed I by a cover or door.-2 whichis normally held closed bylatches -3 car-ried-by the top and the bottom of the box. A pivot rod 4 extends transversely through .therupperportionofthe box or casing and uponthis rodis tiltably mounted a block of insulationconstituting. the -body of the switch. This body or block :is arcuatelongitudinally; as shown in Figure 1,- and is formed in its front 'or outer facecwith: a pocket 6 which occupies themajor portion-of its length and width but is spaced=a greater distance from its upper end than its lower-end in order to provide theblock with a shoulder 1 across the upper end of the pocket.

A combinedstationary contact-and resistance is mounted in-the-pocketfi and-consists of a mountingsheett which is formed of flexible insulatingmaterial and carries a plurality of-resistance coils Sconnected by strips ll] of conductive material; Theresistancecoils and the connecting strips .extend diagonally acrossthe mounting sheet, as .shown in Figures 6 and 7, with the coils bearing against the front face of the sheet and the strips bearing against therear face thereof. Endsof thecoils are connected with ends :ofthe connecting strips .byrivets .I l which passthrouglr the side edge portionsof the sheet. A terminal strip I2 of .conductivematerial.is secured across thelower.endof the sheet by .fasteners 13 and projectsforwardly. from-the sheetand. out-0f thepocket.- The adjacent coil has its terminal portion-9 secured under the head Dione-rivet to establish-electrical connection between the coil and the terminal strip, and midway-its length the v terminal stripv is formed with. an opening Mwhich registers with an opening 15 formed through the block to receivea bolt [6.

tends longitudinally of the block, against the rear This bolt protrudes from the rearface of the blockand in-order that thebolt mayhave a screwdriver applied to it the curved outer portion or lip of. theterminalstrip has a notch 11 formed initQ- A conductor |8eX-'- face thereof, and at its lower end is formed with an opening through which the bolt passes so that this conductor will be firmly held against the block. The upper end of the conductor carries a screw IS in order that a wire 20 may be connected with the conductor. After the sheet carrying the coils and the connecting strips has been fitted into the pocket and disposed against the bottom or inner wall thereof melted insulating material 2! is poured into the pocket about the coils and completely fills the pocket, but portions of the coils protrude from this insulating material. Therefore individual engagement may be made with the convolutions of the coils when the switch is closed, and since the coils extend diagonally in the pocket the resistance will have a long length relative to the length of the pocket.

The movable contact consists of a wide strip or sheet of flexible conductive metal 22 which is of greater length than the block and has its upper end secured flat upon the shoulder 8 by a suitable number of bolts 23 and its lower portion projecting downwardly from the block. One of the bolts has its threaded end portion passing through a conductor strip 24 which extends longitudinally of the block from the upper end thereof and at its lower end carries a terminal screw 25 'to which a wire 28 is secured. When the block is in the position indicated by dotted lines in Figure 1 the movable contact strip or sheet will be out of engagement with the coils and a circuit through the switch will be broken. When the block returns to the position shown in full lines the movable contact sheet moves towards the block and progressively makes contact with the convolutions of the coils. This closes the circuit and as the convolutions Of the coils are engaged the effective length of the resistance formed by the coils and the connecting strips is gradually reduced. Therefore the switch serves as a switch and also as a variable resistance.

The wire 26 is connected with a screw 21 carried by a terminal bracket 28 mounted upon the rear wall of the box I and to this screw is also connected the circuit wire 29. The wire 20 is connected with a screw 39 carried by a conductor strip 3| which is mounted in insulated relation to the rear wall of the box and secured by rivets 32. This conductor strip projects outwardly from the box through an opening in a side wall thereof and. at its outer end carries a screw 33 to which a circuit wire 34 is connected. Current may therefore be supplied through the switch from a source of electric energy to an electrically operated device and by properly adjusting the position of the block the switch may be closed and the extent to which the movable contact engages the resistance coils controlled.

A spring 35 urges the block towards the closed position. This spring has one end engaged with a hook 36 carried by the block midway the width thereof and its other end anchored to an arm or clip 3'! projecting from a carrier 38 which is slidably mounted between tracks 39 for movement vertically along the rear wall of the box to adjusted positions. An eye 40 projects from 'the upper end of the carrier strip 38 and through this eye is swiveled the reduced end of a rod 4| which extends vertically in the box and has its upper end portion thickened and threaded.'

ward movement of the rod and thus shift the carrier 38 to adjusted positions where it is held by action of a locking nut 43. When this nut is tightened the rod will be held against turning and the carrier will be held stationary with the spring 35 under sufficient tension to urge the block 5 towards the position shown in full lines in Figure 1 and causing closing of the switch.

The movable contact strip or sheet 22 extends an appreciable distance beyond the lower end of the block 5 and passes across a roller 43 which is rotatably mounted upon a rod 44 extending transversely of the box. At its lower end the movable contact sheet is secured to a coupling 45 projecting upwardly from the core 46 of a solenoid 41 which rests upon the bottom of the box and has its mounting brackets 48 and 49 secured against the rear wall and the bottom of the box by screws to and 5|. Terminal wires 52 and 53 of the solenoid are engaged with screws 54 and 55 carried by mountings 56 and 51 which are attachedto the rear wall of the box in insulated relation thereto. When current is allowed to flow through the solenoid winding the core 46 is drawn downwardly and pull exerted upon the movable contact strip, thus causing the block 5 to be tilted about the rod H and towards the dotted lined position shown in Figure 1 and open the switch. A pin 58 projects from a side of the core and through a slot formed longitudinally of the cover or door 2, the pin being of such length that its protruding end portion may be readily grapped and the switch manually opened or closed when so desired. A latch 59 is pivoted to the outer surface of the door at one side of the slot for engagement with the pin to releasably hold the pin and the core against upward movement and thus prevent accidental closing of the switch.

Having thus described the invention, what is claimed is:

1. A switch comprising a casing, a block of insulation in said casing pivotally mounted for tilting movement, a fixed contact carried by said block and constituting a resistance having transversely spaced coils connected in series with each other and extending transversely across the block diagonally thereof, a movable contact consisting of a sheet of flexible conductive metal, said movable contact extending longitudinally of the block and having one end secured to an end of the block and its outer end portion free from the other end of the block, means for exerting longitudinal pull upon the movable contact and thereby tilting the block to an adjusted position and progressively moving the movable contact out of engagement with the coils of the resistance, and a spring yieldably holding the block against tilting movement and in its normal position with the movable contact in engagement with the resistance.

2. A switch comprising a casing, a block of insulation in said casing pivotally mounted for tilting movement, a fixed contact carried by said block and constituting a resistance, a movable contact carried by the block and consisting of a strip of flexible sheet metal extending longitudinally of the block with one end secured to one end of the block and its other end portion projecting from the other end of the block, a solenoid in the casing having its core connected with the outer end of the movable contact, the solenoid when energized exerting pull upon the movable contact and tilting the block towards a position disposing the movable contact out of engagement with the resistance, a pin projecting laterally from the core and through a slot in the casing, a latch for engaging the protruding portion of the pin and releasably securing the movable contact and the block in an adjusted position, and spring means for tilting the block towards its initial position when the solenoid is de-energized.

3. A switch comprising a casing, a block of insulation in said casing pivotally mounted for tilting movement, a fixed contact carried by said block and constituting a resistance, a movable contact carried by the block and consisting of a strip of flexible sheet metal extending longitudinally of the block with one end secured to one end of the block and its other end portion projecting from the other end of the block, a solenoid in the casing having its core connected with the outer end of the movable contact, the solenoid when energized exerting pull upon the movable contact and tilting the block towards a position disposing the movable contact out of engagement with the resistance, a track in the easing extending longitudinally therein, an anchor shiftable longitudinally of the track, a spring having one end connected with the anchor and its other end connected with the block and exerting pull to tilt the block towards its normal position with the movable contact in engagement with the stationary contact, and a screw connected with the anchor for shifting the anchor along the track to adjusted positions.

4. A switch comprising a casing, a block of insulation disposed vertically in said casing and pivotally mounted for forward and rearward tilting movement, a fixed contact carried by said block and constituting a resistance having portions extending diagonally across the front of the block and connected in series with each other, a

movable contact formed of flexible conductive L metal and extending longitudinally of said block, along the front face thereof, with its upper end secured to the upper end of the block and its lower end free from the block, a spring having one end connected with the block above its pivot, an anchor for the other end of said spring shiftable vertically in the casing for placing the spring under desired tension and causing the spring to urge the block towards a tilted position disposing the movable contact in engagement with the resistance, and means for exerting downward pull upon the lower end of the movable contact and thereby tilting the block and progressively moving the movable contact out of engagement with the resistance.

5. A switch comprising a casing, a block of insulation disposed vertically in said casing and pivotally mounted for forward and rearward tilting movement, a fixed contact carried by said block and constituting a resistance having portions extending diagonally across the front of the block and connected in series with each other, a movable contact formed of flexible conductive metal and extending longitudinally of said block along the front face thereof with its upper end secured to the upper end of the block and its lower end free from the block, means for exerting pull upon the movable contact and tilting the block to progressively move the movable contact away from the resistance, a spring back of said block having its upper end connected with the block above the pivot for the block, and means for anchoring the lower end of the spring and adjusting the tension thereof to cause the spring to urge the block towards a position separating the movable contact from the resistance.

6. A switch comprising a casing, a block of insulation disposed vertically in said casing and pivotally mounted for forward and rearward tilting movement, a fixed contact carried by said block and constituting a resistance having portions extending diagonally across the front of the block and connected in series with each other, a movable contact formed of flexible conductive metal and extending longitudinally of said block along the front face thereof with its upper end secured to the upper end of the block and its low-= er end free from the block, means for exerting pull upon the movable contact and tilting the block to progressively move the movable contact away from the resistance, a spring back of said 'bloclr. having its upper end connected with the block above the pivot for the block, a mounting carried by the rear wall of the casing and slidable vertically, the lower end of said spring being connected with said mounting, and a rod threaded through the top of the casing and having its lower end swiveled to said mounting whereby turning of the rod will shift the mounting vertically and thereby apply desired tension to the spring and cause the spring to urge the block towards a tilted position for gradually separating the movable contact from the resistance.

WILLIAM E. BAKER.

CES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,364,687 Bentley Jan. 4, 1921 2,211,493 Chappell Aug. 13, 1940 

